1. Field of the Invention
The present invention relates to a method of detecting a vehicle speed and a related electronic device, and more particularly, to an electronic device disposed on a movable emitter for detecting a speed of an external object and a related method.
2. Description of the Prior Art
An operation recorder is a widespread application to be installed on a vehicle, such as a minibus, a container car and a tourist bus. The vehicle operation recorder can record environment information by image and sound when the vehicle moves. As an accident happens, information stored inside the vehicle operation recorder can be utilized to judge illegal duty. However, the conventional vehicle operation recorder is always used after the accident, and can not prevent the accident. Then, design of a new type vehicle operation recorder capable of simultaneously recording the environment information and detecting an approaching vehicle for preventing the hit accident is an important issue to keep travel safety.